1. Field of the Invention
The present invention relates to resolving apparatus for open-end spinning machines having a resolving roller in a housing and a supply roller and a resiliently movable pressure member for feeding sliver through an opening in the housing to the resolving roller.
2. The Problems
Sliver resolving apparatus conventionally includes a resolving roller enclosed in a housing having a sliver infeed opening and fiber discharge opening. The wall of the housing chamber, which contains the resolving roller, normally is concentric with the roller periphery and is spaced from the periphery a sufficient distance to form a fiber feed passage. In order to assure that resolved fibers will travel smoothly at a substantially constant rate through the passage, it is essential that the chamber wall be very smooth. In order to eliminate changes in direction of fiber flow and thereby to streamline the flow, the infeed and discharge opening edges should be faired into the passage wall.
Because of the complicated shape of the housing and the passages through it and because of the need for precision measurements and high quality surface finish of fiber guiding portions of the housing, such housings have conventionally been made of nonferrous metals usually by a die-casting process. In spite of the best skill and quality control in the casting process, the housing walls all too frequently have porous areas and shrink holes. These imperfections often are not detectable until the housing chamber has been machined or polished. Since pores and shrink holes materially and detrimentally affect the quality and rate of productivity of the resolving apparatus, housings so affected must be discarded, resulting in substantial waste of materials and manufacturing work. In particular the housing wall imperfections catch fine fibers, such as cotton, so that the fibers lodge in such holes and pores, resulting in waste of the trapped fibers, interference with passage of the succeeding fibers, and frequent shutdown for cleaning.
A second major problem is that roller housings which are suitable for usage wear rapidly causing decreased quality and efficiency of production over time and must be scrapped and replaced at frequent intervals. While nonferrous metals are the most reliable for die-casting and polishing, they are subject to wear and erosion, especially when used for housings which process synthetic fibers. In a threestage continuous operation of sliver feed, fiber resolving and fiber spinning using a sliver supply speed of approximately 150 meters per minute using sliver of No. 5 fineness, the hourly fiber production is about 2 kilograms. The wear rate for such production is so great that the useful life of the housings is about one year, after which they must be scrapped. Wear is especially severe at the margins of the sliver infeed, the fiber discharge and, if provided, the dirt discharge openings in the housing, which wear is accelerated when matted synthetic fibers are being processed. This type of wear results in deterioration in fiber flow into, through and out of the housing which, in turn, increases fiber waste, reduces reliability of output and increases downtime for maintenance.
The pressure member of the sliver feed mechanism for the resolving apparatus is resiliently mounted relative to the supply roller to permit movement to compensate for variations in sliver thickness or density. Sliver feed mechanism of this type is shown in U.S. Pat. No. 3,695,022, in which the direction of pressure member movement is perpendicular to a resolving roller radius through a sliver infeed opening in the resolving roller housing. In FIG. 1 of West German Offenlegungschrift 2,312,169, resolving apparatus is shown in which the movement of the pressure member is circumferentially of the resolving roller. The sliver feed mechanism is located as close to the resolving roller as possible, which is accomplished by providing a large opening in the resolving roller housing, which opening is partially covered by the supply roller and pressure member. This construction raises a third problem however. In order to permit movement of the pressure member, it has been necessary to provide some play between the housing wall and the pressure member, which has provided spaces and gaps large enough that dust, fibers and sliver pieces can escape from the resolving device and/or settle in the spaces, resulting in waste of fiber, clogging of the gaps and binding of the pressure member. The result is a material reduction in the efficiency and capacity of the resolving apparatus.